The Trijicon VCOG (Variable Combat Optical Gunsight) optical sight is by far one of the most durable variable power optics available today. The Trijicon VCOG is built from the ground up to be able to stand up to the rigors of extreme combat and duty use in any environment. The VCOG is a Military Specification grade optic robust enough for any application. The variable power allows for use as both a CQB and long distance marksmanship. Don't accept knock offs or inferior products when your life is on the line go with the very best, go with a Trijicon VCOG.